Oxidation of alcohol



- hyde.

Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE OXIDATION OF ALCOHOL Joseph E. Bludworth, Cumberland, Md., assignor to Celanese Corporation of America, a corporation of Delaware No Drawing. Application March 17, 1939.

Serial No. 262,506

14 Claims.

This invention relates to the oxidation of ethyl alcohol or other alcohols, and relates more particularly to the oxidation of such alcohols by means of air or otheroxygen containing gas.

. An object of my invention is to oxidize alcohols in a more'economical and expeditious manner than has been heretofore possible. A fur ther object of my invention is to provide a process' for the simultaneous oxidation of alcohols and aldehydes. Other objects of my invention will appear from the following detailed description.

It has heretofore been proposed to oxidize ethyl alcohol by means of air to form acetalde- However, this process requires high temperatures, on the order of 900 F. or more, and

produces relatively low yields of acetaldehyde for each pass of the reactants through the reaction chamber.

may be varied within very wide limits and in the case of acetaldehyde it may be from 0.3% to 400% or more of the weight of the ethyl alcohol being oxidized. As an example of the effect of '5 the amount of acetaldehyde present on the temperature of reaction required to obtain good yields in the oxidation of ethyl alcohol, it is pointed out that it is 900 F. when no acetaldehyde is present, 800 F. when 0.3% acetaldehyde is present, 650 F. when 50% of acetaldehyde is present, and 575 F. when 200% acetaldehyde is present, the percentages being based on the weight of the ethyl alcohol present.

While I prefer to employ air as the oxidizing 1'5 agent, free oxygen or any suitable gascontaining free oxygen may be employed. The amount of oxygen present is preferably not sufiicient to oxidize all the alcohol and aldehyde present, but is preferably from to 50% of the-theoretical I have found that if the alcohol is oxidized in 20 amount requiredthe presence of a substance oi.a material capable of oxidizing at a lower temperature such as tical effects the process can be considered as one yielding acid by theoxidation of an alcohol.

While this invention is particularly useful in connection with the oxidation of ethyl alcohol, it may be used for the oxidation of other alcohols such as methyl alcohol, propyl alcohol or butyl alcohol.

As stated, the oxidation promoting material is one that either oxidizes at a lower temperature than the alcohol to be oxidized, such as acetaldehyde, formaldehyde or ethylene oxide (which rearranges to form acetaldehyde) or which generates heat by otheraction such as rearrangement, such as ethylene oxide, propylene oxide, or isobutylene oxide, or methallyl alcohol, which rearranges to isobutyric aldehyde. In order to avoid complications arising from having the resulting products containing a multiplicity of products that require separation, I prefer to em- 50 the reaction chamber or tubes consist of uncon to the alcohol being treated, and therefore the ploy as the promoter the aldehyde corresponding invention will be further described in connection with the. oxidation of ethyl alcohol in the presence of acetalclehyde.

In order to cause the oxidation to proceed more smoothly, I prefer to carry it out in the presence of steam, or other diluents say from 0.2 to 30 parts by weight for each part of 'thealcohol present. Other inert diluents such as nitrogen may be present in addition to or instead of. part of the steam.

While the reaction proceeds satisfactorily at atmospheric pressures, sub-atmospheric pressures or super-atmospheric pressures up to 50 lbs. per square inch may be used.

During the oxidation, part of the ethyl alcohol is oxidized to acetaldehyde and the acetaldeliyde that was initially present, and in some cases 5 part of the acetaldehyde that is formed, is oxidized to acetic acid. However, conversion is not complete in one passage through the reactor and if desired the reaction mixture with the repeated addition of further quantities of air or other oxy- 40 gen containing gas may be passed through a series of reactors. Alternatively the products from the reactor may be condensed and the unconverted ethyl alcohol and acetaldehyde recovered and reused in the process while the recovered acetic acid is retained as the end product.

Another and important variation of my process is the recycling of part of the products leaving the reaction chamber but prior to their con= ,densation or separation. lloe products leaving steam, nitrogen (from the air) with or without unconsumed oxygen, carbon dioxide and. carbon monoxide. These products are in gaseous or The amount of oxidation promoter employed at vaporous form. A predetermined portion of this the desired operating pressure.

is sent to the condensers etc. for separation and recovery of the products, but the remaining portion (which may be cooled to some degree) while still hot and containing its constituents in vaporous or gaseous form is recycled with a fresh quantity of reactants to the reaction chamber or tubes. When air is'used as the oxidizing agent, the amount of products recycled will be governed by the amount of nitrogen it is necessary to withdraw from the final condenser to maintain The amount of fresh reactants added is so regulated with respect to the composition oithe recycled gases and vapors to give the proportion of alcohol, aldehyde, oxygen, and other constituents desired. By this hot recycling method the cost of condensing, recovery, and reheating the constituents for further reaction is avoided.

I It will be seen that the'process can be so regulated by recycling the acetaldehyde that the from the outside is the ethyl alcohol and the only material withdrawn from the system is aceit may be considered as a method of producing acetic acid directly from ethyl alcohol, when all the acetaldehyde leaving the oxidation zone is recycled back to the oxidation process.

In order to further illustrate my invention but without being limited thereto, the following specific examples are given.

Example I A reaction mixture consisting of the following ingredients is used.

Parts by weight Ethyl alcohol 1 Acetaldehyde -1 1.077 Air 1.055 Steam- 0.196

is passed through a tube or chamber of inch Ethyl alcohol, acetaldehyde, steam and air are passed through the apparatus described in Example I at a temperature of 525 F. The products leaving the reaction tubes are recycled in such proportions and with the addition of such 7 only material to be oxidized that is introduced tic acid, so that from the practical point of view required ingredients that an equilibrium" is reached wherein the product leaving the reaction chamber consists of the following:

, Parts by weight Ethyl alcohol 1.0 Acetaldehyde 0.956 Acetic a i 11.37 Steam 5.85 Nitrogen 25.3

The process proper is then proceeded with by taking97.68% 'of the products leaving the rerecycled 1 part by weight of ethyl alcohol and 3.11 parts by weight of air.

In this manner there is recovered 0.095 part by weight of ethyl alcohol, 0.091 part by weight of acetaldehyde, and 1.086 parts by weight of acetic acid for each part by weight of fresh ethyl alcohol introduced into the system. v

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. Process for the oxidation of an alcohol,'

which comprises feeding the vapor of said alcohol in admixture with 50 to 200% of its weight of the vapor of a substance selected from the class consisting of formaldehyde, acetaldehyde,

ethylene oxide, propylene oxide, isobutylene oxide and methallyl'alcohol and in admixture with a gas containing free oxygen into a heated reaction zone and effecting oxidation within that zone in the absence of a solid catalyst.

2. Process for the oxidation of an alcohol, which comprises feeding the vapor of said alcohol in admixture with 50 to 200% of its weight of the vapor of a substance selected from the class consisting of formaldehyde, acetaldehyde, ethylene oxide, propylene oxide, isobutylene oxide and methallyl alcohol and in admixture with a gas containing free oxygen into a heated reaction zone, effecting oxidation within that zone, removing a small proportion of the issuing gas mixture and recovering the condensible constituents therefrom, admixing fresh alcohol vapor with the remainder of said gas mixture and recirculating the resulting alcohol-gas mixture through the reaction zone in the absence of a solid catalyst. I

'3. Process for the oxidation of an alcohol, which comprises feeding the vapor of said alcohol in admixture with 50 to 200% of its weight of the vapor of the corresponding aldehyde and in admixture with a gas containing free oxygen into a heated reaction zone and efiecting oxidation within that zone in the absence of a solid catalyst.

4. Process for the "oxidation of an alcohol, which comprises feeding the vapor of said alcohol in admixture with 50 to 200% of its weight of the vapor of the corresponding aldehyde and in admixture with a gas containing free oxygen into a heated reaction zone, effecting oxidation within that zone, removing a small proportion of the issuing gas mixture and recovering the condensible constituents therefrom, admixing fresh alcohol vapor with the remainder of said gas mixture and recirculating the resulting alcohol-gas mixture through the reaction zone in the absence of a solid catalyst.

5. Process for the oxidation of an alcohol, which comprises feeding into a heated reaction zone the vapor of said alcohol in admixture with 50 to 200% of its weight of the vapor of the corresponding aldehyde and in admixture with oxygen in amount equal to 20 to 50% of that theoretically required for oxidizing the alcohol and aldehyde tothe corresponding acid, and 20 to 3000%, based on the weight of the alcohol, of a diluent and effecting oxidation within that zone in the absence of a solid catalyst.

6. Process for the oxidation of an alcohol, which comprises feeding into a heated reaction zone the vapor of said alcohol in admixture with a reaction z'one.

aaeaoor 3 50 to 200% of its weight of the vapor of the corresponding aldehyde and in admixture with oxygen in amount equal to 20 to. 50% of that theoretically required for oxidizing the alcohol and aldehyde to the corresponding acid, and 20 5 7. Process'for the oxidationof ethyl alcohol,

" whichv comprises feeding the vapor of said ethyl alcohol in admixture with 50 to 200% of its" weight of the vapor of acetaldehyde and in admixture with a gas containing. free oxygen into a heated reaction zone and .eflecting oxidation within that zone in the absence of a solid catalyst. 8. Process for the oxidation of ethyl alcoh which comprises feeding the vapor of, said et yl alcohol in admixture with 50 to 200% of its weight or the vapor ofacetaldehyde and'in admixture with a gas containing free oxygen into aheated reaction zone, effecting oxidation within that zone in the absence of a 'solid catalyst, re-

moving a small proportion of the issuing gas mixture and recovering the condensible constituents therefrom, admixing fresh ethyl alcohol vapor with the remainder of said gas mixture and recirculating the-resulting alcohol-gas mixture through the reaction zone.

which comprises feeding into a heated reaction zone the vapor of said ethyl alcohol in admixture with to 200% of its weight of the vapor of acetaldehyde and in admixture with'oxygen in amount equal to 20 to 50% of that theoretically 4 required for oxidizing the ethyl alcohol and aldehyde to the corresponding acid, and 20 to 3000%,-

based on the weight of the ethyl alcohol, of a diluent and effecting oxidation within that'zone in the absence of a. solid catalyst.

' l 10. Process for the oxidation of ethyl alcohol,

which comprisesfeeding into a heatedreaction' zone the vapor of said ethyl alcohol in admixture with 50. to 200% of its ,weight of the vapor of acetaldehyde and in admixture with oxygen in amount equal to 20 to 50% of that theoretically required for oxidizing the ethyl alcohol and aldehyde to the corresponding acid, and 20 to 3000%,

based on the weight of the ethyl alcohol, of a diluent eflecting oxidation within that zone inmainder of said gas mixture and recirculating the resulting alcohol-gas mixture through the reaction zone. r

v 11. Process 'for the oxidation of ethyl alcohol, which comprises feeding the vapor at said-ethyl alcohol in admixture with 50 to 200% of its weight of the vapor of acetaldehyde and in admixture with a gas containing free oxygen into a heated reaction zone and effecting oxidation at a temperature between 575-and 650- F. within that zone in the absence of a solid catalyst.

' 12.'Process for'the oxidation .of ethyl alcohol.

' which comprises feedingthe vaporof said ethyl alcohol in admixture with 50 ,to 200% ,of its weight of the .vapor of acetaldehyde and in admixture with a gas containing free oxygen'into a heated reaction zone, eil'ecting oxidation within that zone at a temperature between 575 and 650 F removing a small proportion of the issuing gas mixture and recovering the condensible constituents therefrom in the absence of a solid catalyst, admixing fresh ethyl alcohol vapor with the remainder of said gas mixture and recirculating the resulting alcohol-gas mixture through the reaction zone.

13. .Process for the-oxidation of ethyl alcohol,

w ich comprises feeding the vapor of said ethyl alcohol in admixture with '50 to 200% of its weight of the vapor 'of acetaldehyde and in admixture with oxygen in amount equal to 20 to 50%, of that theoretically required for oxidizing theethyl alcohol and aldehyde to the corresponding acid, and 20 to 3000%, based on the I weight of the ethyl alcohol or a diluent into a 9. Process for the oxidation of ethyl alcohol, 35

heated reaction zone and efiecting oxidation within that zone at a temperature between 575 and 650 F. in the absence of a solid catalyst,

the time of contact being about, one second.

14. Process for the oxidation or ethyl alcohol. which comprises feeding into a heated reaction zone the vapor of said ethyl alcohol in admixture with 50 to 200% of its weight of the vapor of acetaldehyde and-in admixture with oxygen in amount equal to 20 to 50% of that theoretically 5. required for oxidizing the ethyl alcoholand aldehyde to the corresponding acid, and 20 to 3000%,

based on the weight of the ethyl alcohol, of a diluent, efiecting oxidation within that zone at a temperature. between 575 and 650 F. in the absence of a solid catalyst, the tim of contact-t being about one second, removing a small proportion ofthe issuing gas mixture and recovere ,i'ng the'condensibie constituents therefrom, ad-

mixing fresh ethyl alcohol vapor with the remainder ofsaid gas mixture and recirculating the resulting alcohol-gas mixture through the re.-

action zone. JOSEPH E. BLUDWORTH. 

